[lwip-users] Misalignment problems on PowerPC (little endian mode)

[Muhamad Ikhwan Ismail]

Hi,

I am interested in knowing if there is any other user of lwip who has managed to implement lwip in PowerPC (little endian mode)
and got rid of the lil endian misalignment exceptions ? As lwip strips the Ethernet header (14 bytes) the IP addr fields (4 bytes) in the IP header sits on
a non-aligned address.My FEC is setup in a way that all received buffers are stored directly into the pbufs instead of a temporary buffer to minimize latency,
so the ethernet padding option does not really work for me. The FEC can only save frames into addresses multiple of 16 only.

 So for me (as far as my knowledge limits me  :) ) there 2 other possibilities left, one is packing the structure, or apply changes on the ip address
functions and macros so that it works with the ip address as 2 16 bit fields instead of 1 32 bits field. Unfortunately I couldnt make structure packing
work with my compiler (Wind River Compiler). I am interested in knowing if anyone has done the same thing and mind sharing experience ? Any
thoughts,ideas and feedbacks would also be welcomed.

ps: I have an alignment fixing subroutine, but then again we want to minimize the latency.

Greetings and thanks in advance
Ikhwan Ismail
ABB STOTZ-KONTAKT GmbH
Heidelberg
Germany

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